PAT 1148 Werewolf - Simple Version-CFANZ编程社区

1148 Werewolf - Simple Version (20分)

Werewolf（狼人杀） is a game in which the players are partitioned into two parties: the werewolves and the human beings. Suppose that in a game,

player #1 said: "Player #2 is a werewolf.";
player #2 said: "Player #3 is a human.";
player #3 said: "Player #4 is a werewolf.";
player #4 said: "Player #5 is a human."; and
player #5 said: "Player #4 is a human.".

Given that there were 2 werewolves among them, at least one but not all the werewolves were lying, and there were exactly 2 liars. Can you point out the werewolves?

Now you are asked to solve a harder version of this problem: given that there were N players, with 2 werewolves among them, at least one but not all the werewolves were lying, and there were exactly 2 liars. You are supposed to point out the werewolves.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (5≤N≤100). Then N lines follow and the i-th line gives the statement of the i-th player (1≤i≤N), which is represented by the index of the player with a positive sign for a human and a negative sign for a werewolf.

Output Specification:

If a solution exists, print in a line in ascending order the indices of the two werewolves. The numbers must be separated by exactly one space with no extra spaces at the beginning or the end of the line. If there are more than one solution, you must output the smallest solution sequence -- that is, for two sequences A=a[1],...,a[M] and B=b[1],...,b[M], if there exists 0≤k<M such that a[i]=b[i] (i≤k) and a[k+1]<b[k+1], then A is said to be smaller than B. In case there is no solution, simply print No Solution.

Sample Input 1:

5
-2
+3
-4
+5
+4

Sample Output 1:

1 4

Sample Input 2:

6
+6
+3
+1
-5
-2
+4

Sample Output 2 (the solution is not unique):

1 5

Sample Input 3:

5
-2
-3
-4
-5
-1

Sample Output 3:

No Solution

对狼人杀这种游戏一直都很迷，看了好久才看懂题意……

题意：n名玩家，其中狼人有两位，其他都是人类，让你找出两位狼人序号。游戏中规定说谎的人有两位，说谎的狼人至少有一个但不是全部，所以说一个狼说假话，一个人类说假话。如果没有解输出 No Solution，多个解输出最小序列

方法：可以假设两个狼人，然后从头判断玩家说的话，如果玩家说的身份跟假设的身份不一样说明其说谎，如果最后说谎的人数是2并且一个是好人一个是狼人，则满足题意，否则输出“No Solution”

#include <bits/stdc++.h>
using namespace std;
int main(){
  int n;
  
  cin >> n; 
  vector<int> v(n+1);
  for(int i = 1; i <= n; i++)
    cin >> v[i];
  for(int i = 1; i <= n; i++){
    for(int j = i+1; j <= n; j++){
      vector<int> lie,a(n+1, 1);
      a[i] = a[j] = -1; //i,j都是狼人
      for(int k = 1; k <= n; k++){
        if( v[k] * a[abs(v[k])] < 0 ) lie.push_back(k);
        //自己说的跟假设的情况不一样，说明第k个人在说谎 
      } 
      if(lie.size() == 2 && a[lie[0]] + a[lie[1]] == 0){
        cout << i << " " << j << endl;
        return 0;
      }
    }
  }
  cout << "No Solution" << endl;
  return 0;
}